Spile

Correct the offset error by moving the secondary towards the primary so that a=b, getting rotation as good as you can. Then adjust tilt/rotation.

I’d set up a Google Drive folder for this. You can even use it to share files with others. I use it all the time.

8 hours ago, wookie1965 said:

Here Spile does this look better. 

I will take look tomorrow but it would be a lot easier if placed a piece of paper behind the focuser so that I could see all the edge of the sight tube.

This is where you need to be:

I'm seeing mainly rotational error so I'd loosen the centre bolt, rotate, tighten and tweak fine adjustments (three outer bolts) as necessary.

No it sounds like focus issue to me. The blue and yellow components are very wide and should be easy prey for your telescope.

7 hours ago, Lurcher said:

And as I want to change to small finderscope on the StellaLyra one day

Why would you want to change the RACI?

12 hours ago, Richard N said:

It should of course; but does it? Comments suggest not in all cases. 

What I have found is that as long as the collimation bolts and spider fixings are tight then the mirrors don’t move. I haven’t changed the springs on my primary because I see no reason to.

22 hours ago, Mandy D said:

@Spile Thank you. That is clearer, now. However, the two words concentric and circular work for most people and require no further explanation and no need to keep referring back to a diagram.

That’s my point - words work for some but others like me prefer diagrams or photos and as we all learn in different ways, having a range of different guides is  great.

11 hours ago, Richard N said:

And just to worry folks, if you collimate with the scope horizontal, does the collimation remain accurate for all elevation angles? 

Yes it should.

47 minutes ago, Richard N said:

And just to worry folks, if you collimate with the scope horizontal, does the collimation remain accurate for all elevation angles? 

Yes - if it doesn't I'd be checking the tightness of your lock bolds/stiffness of your springs for the primary and tightness of the spider and 3 outer bolts for the secondary.

8 hours ago, Mandy D said:

@Spile a=b, b=c, d=e? It would help us all if you could perhaps indicate what these letters represent.

It’s how I avoid using terms like roundness and concentric in my collimation guide in an attempt to reduce the number of words used to describe the intended result…

My suggestion is that you find a guide that makes sense to you and stick with that. Trying to combine advice from different authors would be like following a recipe from Delia Smith, Ken Hom and Mrs Beeton at the same time. I wrote my guide because I wanted to put into words and most importantly diagrams, the words of people I trust to get it right. Aka Vic, Jason and Don. If it helps someone else then that’s a bonus but the prime reason for doing it was for myself. I’ve used letters and diagrams rather than descriptions because it’s clearer to me.

Collimation should never stop anyone from getting a reflector. Its like riding a bike, it takes time and can be scary at first but once you’ve mastered it, you’ll be set for life.

1 hour ago, Astroscot2 said:

I find making adjustments to the secondary a real chore, the changes required are minute to align the reflections,  must be a better solution mechanically than the push/pull of the secondary screws, I find myself going around and around with the adjustments.

Mark

Start with the offset and move the secondary towards or away from the primary in order to get a=b and to get the rotation error as minimal as possible. That will be a coarse adjustment because the central screw will be loose. Next adjust the three outer bolts (the fine adjustment) to correct the tilt/rotation so that b=c and d=e. 
I don’t recommend covering the reflection of the primary mirror. The dark  offset secondary “pointing” away from the focuser is an alignment check.

2 hours ago, lawsio said:

Right, after too many hours of fettling I'm back. I think it's better now but not 100%.

A couple of things;

- I am absolutely 100% adamant I can't see more than one primary clip at a time in the secondary. If I take the cheshire out and look directly onto the secondary I can see where all three are if my move my eye about but never all at the same time.

- I live in Cheshire and I'm going to have to move because the whole place reminds me of collimators now.

- If anyone's wondering if telescopes float, I might have the answer for you very soon!

 

This is where you need to end up...

Ignore the mirror clips (step 3) until you have confirmed that e=f , a=b and c=d (step 1) and that the cross hairs of the sight tube intersect with the centre mark and dark offset secondary reflection (step 2).

Ref  https://astro.catshill.com/collimation-guide/

I posted a link to the collimation guide on my site but it appears that the moderators removed it.

Start by moving the secondary away from the primary so that a=b, and at the same time get the coarse rotation as good as you can. Next, fix the tilt/rotation error; you should be much closer. Ignore the primary tilt until the secondary is sorted.

41 minutes ago, Mandy D said:

Which scope are you trying to collimate? I did my 200P's secondary mirror yesterday and got all three clips in view. It was a little tricky, but certainly possible. 

Yes but only when after …

1. The outer edges of the primary mirror and secondary mirror are circular (e=f) and concentricwith the edge of the sight tube, so the secondary is centred (a=b and c=d) in respect of the focus tube.

2. The crosshairs of the sight tube intersect with the centre mark and the dark offset secondary reflection (x2) is offset toward the primary mirror. 
 

I tried to overlay circles on the second image but the edge of the focus tube was too undefined. Place a piece of paper (as per the link above) behind the focuser and take the photo through the cap again.

Meanwhile, this shows the secondary error from the first image...

The most obvious error is c≠d which indicates tilt/rotation errors (https://astro.catshill.com/collimation-guide/) 

I would also expose the primary mirror as the reflection will give an indication of the error. See step 2 of the primary check.

I can recommend Saturn and the Saturn Nebula which coincidentally are pretty close to one another at the times. 61 Cygni is a nice looking double that is worth looking at.

I’ve used a Dobsonian that didn’t have enough friction and I was glad to get back to my 200P.

I use toiletry bags for eyepieces and collimation tools. I then put these in a rectangular plastic box along with head torch, sketch pad etc etc.

I’ve read about folk lubricating the pads but then needing to reapply lubricant a few months later. I have not applied anything to my pads or bearings in two years and I am not aware of any increased friction. If I do, I’ll simply clean them.

Finally got my first clear skies in months. No perseids but started with Alberio, the beautiful coloured double in Cygnus before moving to the much tighter Izar in Bootes. Then a few Messier objects in in and around Sagittarius (M29, M24, M20, M28) . Saturn was as impressive as ever with the rings more edge on than last time I observed it. Finished with the mesmerising M13 In Hercules.